Daylight Savings Time

9 months ago

What is Daylight Saving Time?

Daylight Saving Time (United States) 2015 begins on Sunday, March 13th 2016 at 2:00AM and ends Sunday, November 6th

DOES DAYLIGHT SAVING TIME REALLY SAVE ENERGY? There have been a number of conflicting reports about how much energy is saved from Daylight Saving Time. Back in the 1970s, studies showed we saved 1% of energy nationally, which was a big motivation for adopting DST. On the one hand, states like California argue the energy savings are negligible. But another report published in 2008 by the U.S. Department of Energy concluded 4 weeks extra of daylight savings time could conserve 1.3 trillion watt-hours per day, enough to power 100,000 homes for a year. ... Though Benjamin Franklin first came up with the idea in 1784, DST wasn't used until World War I to conserve energy. The U.S. observed year-round DST during World War II and implemented it during the energy crisis in the 1970s.

See The World Clock for current times and places observing daylight saving time (DST) at the moment.

Daylight Saving Time (or summertime as it is called in many countries) is a way of getting more light out of the day by advancing clocks by one hour during the summer. During Daylight Saving Time, the sun appears to rise one hour later in the morning, when people are usually asleep anyway, and sets one hour later in the evening, seeming to stretch the day longer.

Many locations in the world set their clocks from 2am (or 02:00) to 3am (or 03:00) in their local times when they begin daylight saving time. However, some places change their clocks at other times, depending on the daylight saving time rules.

When Do the Clocks Change?

Northern Hemisphere

Daylight saving time begins in the northern hemisphere between March–April and ends between September–November. Standard time begins in the northern hemisphere between September–November and ends between March–April. Many countries in the northern hemisphere may observe DST.

Southern Hemisphere

Daylight saving time begins in the southern hemisphere between September–November and ends between March–April. Standard time begins in the southern hemisphere between March–April and ends between September–November. Many countries in the southern hemisphere may observe DST.

Why Observe DST?

Many countries observe DST, and many do not. The reason many countries implement DST is in hopes to make better use of the daylight in the evenings, as well as some believe that it could be linked to reducing the amount of road accidents and injuries. The extra hour of daylight in the evening is said to give children more social time with friends and family and can even boost the tourism industry because it increases the amount of outdoor activies.

DST is also considered as a means to save energy due to less artificial light needed during the evening hours—clocks are set one hour ahead during the spring, and one hour back to standard time in the autumn. However, many studies disagree about the energy savings of DST and while some may show a positive outcome of the energy savings, others do not.

It is difficult to predict what will happen with Daylight Saving Time in the future. The daylight saving date in many countries may change from time to time due to special events or conditions.The United States, Canada and some other countries extended DST in 2007. The new start date is the second Sunday in March (previously the first Sunday in April) through to the first Sunday in November (previously the last Sunday in October).

Brief History of DST

Benjamin Franklin first suggested Daylight Saving Time in 1784, but modern DST was not proposed until 1895 when an entomologist from New Zealand, George Vernon Hudson, presented a proposal for a two-hour daylight saving shift to the Wellington Philosophical Society.

The conception of DST was mainly credited to an English builder, William Willett in 1905, when he presented the idea to advance the clock during the summer months. His proposal was published two years later and introduced to the House of Commons in February 1908. The first Daylight Saving Bill was examined by a select committee but was never made into a law. It wasn't until World War I, in 1916, that DST was adopted and implemented by several countries in Europe who initially rejected the idea. There is more information about the history of DST on our website.

In which direction does the clock move?

The clock moves ahead (thus, losing one hour) when DST starts, typically in the spring, and falls back one hour (thus, gaining one hour) when DST ends in the fall. To make it easier to remember which way the clock goes, keep in mind one of these sayings: “spring forward, fall back” or “spring ahead, fall behind.”

Is DST always one hour ahead of normal time?

Today it is almost always one hour ahead, but throughout history there have been several variants on this, such as half adjustment (30 minutes) or double adjustment (two hours), and adjustments of 20 and 40 minutes have also been used. A two-hour adjustment was used in several countries during the 1940s and elsewhere at times.

A half adjustment was sometimes used in New Zealand in the first half of the 20th century. Australia's Lord Howe Island (UTC+10:30) currently follows a DST schedule that moves its clocks forward half an hour to UTC+11, which is Australian Eastern Daylight Time (AEDT) when it is on DST.

Sometimes DST is used for a longer period than just the summer, as it was in the United States during World War II. From February 3, 1942 to September 30, 1945 most of the United States had DST all year; it was called “War Time.”